Oven Temperature: 500F, then 450F,Six hours or up to 3 days ahead, make the starter (biga).,In a small bowl, combine all the ingredients for the biga and stir the mixture with a wooden spoon for 3 to 5 minutes or until it is very smooth and pulls away from the sides of the bowl.,The biga should still be tacky (sticky) enough to cling slightly to your fingers.,Cover the bowl tightly with oiled plastic wrap (or place it in a 2-cup food storage container with a lid) and set aside until tripled and filled with bubbles.,At room temperature, this will take about 6 hours.,Stir it down and use it, or refrigerate it for up to 3 days before baking.,Mix the dough.,In the mixer bowl, whisk together the all-purpose flour, durum flour, and yeast.,Then whisk in the salt (this keeps the salt from coming into direct contact with the yeast, which would kill it).,Add the water and the biga.,Using the paddle attachment, mix on low speed for about 1 minute, until the flour is moistened enough to form a rough dough.,Change to the dough hook, raise the speed to medium (#4 KitchenAid), and beat for 5 minutes to form a smooth, sticky dough.,If the dough does not pull away form the bowl after 5 minutes, beat in more flour 1 teaspoon at a time.,The dough should still stick to the bottom of the bowl and cling to your fingers.,If it is not sticky, spray it with a little water and knead it in.,Let the dough rise.,Sprinkle durum flour generously on to a counter in a 6-inch square.,Using a wet or oiled spatula or dough scraper, scrape the dough onto the flour, and dust the top of it with more flour.,(The flour will be absorbed into the wet dough.),______,With floured hands, pull out two opposite sides of the dough to stretch it to double its length, and give it a business letter turn.,Dust it again with flour, cover it with plastic wrap, and allow it to rest for 30 minutes.,Repeat the stretching, folding, and flouring a second time, and again allow the dough to rest for 30 minutes.,Repeat the stretching, folding, and flouring a third time, then round the edges of the dough.,Using and oiled spatula or dough scraper, transfer the dough to a 2-quart dough-rising container or bowl, lightly greased with cooking spray or oil.,Cover the container with a lid or plastic wrap.,Using a piece of tape, mark the side of the container at approximately where triple the height of the dough could be.,Allow the dough to rise (ideally at 75F to 80F) until tripled, about 2 hours.,Preheat the oven.,Preheat the oven to 500F 1 hour before baking.,Have an oven shelf at the lowest level and place an oven stone or baking sheet on it, and a cast-iron skillet or sheet pan on the floor of the oven, before preheating.,Shape the dough and let it rise.,Dust a counter well with durum flour.,With floured hands or a floured dough scraper, gently transfer the dough to the counter.,Handling the dough very gently, to maintain as much as possible, round it into a ball.,(See Notes),Gently set the dough seam side up in a floured banneton or a colander lined with a floured towel.,Pinch together the seam if necessary.,Sprinkle the top lightly with flour, and cover with a large container, or cover loosely with oiled plastic wrap.,Allow the dough to rise until it has increase by about 1 1/2 times, to 1 1/2 hours.,(In the banneton, it will just begin to push up the plastic.,Bake the bread.,Remove the container or plastic wrap, invert the lined baking sheet on top of the banneton or colander, and invert the dough onto the sheet.,(If you used a colander and floured towel and the risen bread is more than 1 inch below the top, you will need to support the bread when inverting it so that it doesnt fall and deflate.,Cut a cardboard circle small enough to fit into the colander and touch the surface of the bread.,Place a piece of parchment on top of the bread, place the cardboard on top, and invert the bread onto the cardboard.,Slide the bread, still in the parchment, onto the baking sheet.),Or, if using a cornmeal-sprinkled baking sheet, invert the dough directly onto it.,Quickly but gently set the sheet on the baking stone or baking sheet.,Toss 1/2 cup of ice cubes onto the pan beneath and immediately shut the door.,Bake for 5 minutes.,Lower the temperature to 450F and continue baking for 15 to 25 minutes or until the bread is deep golden brown (an instant-read thermometer inserted into the center will read about 205F).,Halfway through baking, with a heavy pancake turner, lift the bread from the pan and set it directly on the stone, turning it around for even baking.,Cool the bread.,Remove the bread from the oven and transfer it to a wire rack to cool completely.,Ultimate Full Flavor Variation:,For the best flavor development, in Step 1, allow the biga to ferment in a cool area (55F to 65F) for 12 to 24 hours.,(A wine cellar provides an ideal spot.),After 12 hours, it will have tripled and be filled with bubbles; it will not deflate even after 24 hours at this cool temperature.